The cameras are small, black domes resembling those common in department stores and airports. There are four per car and three on each platform, said Florida Department of Transportation spokesman Steve Olson.

"It's basically a security tool for us, it gives us an idea what's happening," Olson said. Asked about the potential for privacy concerns, he added: "We live in a society now where our actions, even out on public streets, are recorded."

The cameras on the trains record but don't send out a live feed, he said. Those on the platforms feed live video to the SunRail operations center in Sanford. Olson said the feeds are only monitored as needed; there's not always someone watching.

The external cameras can be helpful, especially when there's a crash, Arnold said: "When an incident happens we can download them and show them to the police."

Olson said aspects of SunRail's surveillance system are still being worked out, including how long to store the video and how best to coordinate with local law enforcement when police agencies need SunRail video.

"We're having those discussions right now," Olson said.

Several riders at the Lynx Central station on Friday said that they were glad the cameras were there. Some said they assumed they were being watched, and were comforted by the notion.

"Anything can happen, at least we have something," said Lauren Jeffress.

Jeffress, who hails from Washington, D.C., said she's used to surveillance and is happy to have the opportunity to return to commuter rail, describing SunRail as "convenient and very fast."

Sylvia Pryor, a first-time rider, said she "would feel safe knowing that they have cameras," though she added that people should be told they're being filmed, "out of respect."

Valerie Washington, who was also riding for the first time Friday, said she's not opposed to security cameras, but "there should be signs telling you that you're being taped," and explaining why.

There aren't any such signs, either on the trains or platforms. Jeramie Scott, national security counsel for the Electronic Privacy Information Center, said the use of cameras in public without disclosure is "definitely questionable."

"Notice to the public is essential for surveillance cameras, and the fact they didn't do that is problematic," he said.

Rob Walls, who was making his second attempt to get a ride on the still-crowded train service on Friday, said the cameras are conspicuous enough that their presence is apparent: